Slack is updating the API Terms of Service, effective May 29, 2025 for new applications and June 30, 2025 for existing applications.
Also effective May 29, 2025, all newly-created Slack apps that have not been approved for the Slack Marketplace will be subject to new rate limits for the conversations.history and conversations.replies API methods. This change will also impact net new installations of applications distributed outside the Marketplace. Beginning September 2, 2025, existing installations and apps that are not Marketplace-approved will be subject to the new posted limits.
The rate limits for both the conversations.history and conversations.replies API methods are changing from Tier 3 to Tier 1 for apps that are not approved for the Slack Marketplace:
conversations.history - The conversations.history API method rate limit for apps created after May 29, 2025, and for net new installations of existing apps, will be limited to 1 request per minute, unless they are approved for the Slack Marketplace. The maximum and default for the limit parameter has been reduced to 15 objects.
conversations.replies - The conversations.history API method rate limit for apps created after May 29, 2025, and for net new installations of existing apps, will be limited to 1 request per minute, unless they are approved for the Slack Marketplace. The maximum and default for the limit parameter has been reduced to 15 objects.
Read on for more granular answers to the questions you may be thinking. And of course, let us know if you have any questions, concerns, or suggestions about these changes. Thank you!
You can read the full terms here but below is a summary of what's changing:
Commercial Distribution: The updated terms confirm that the Slack Marketplace is the only appropriate channel for commercially distributing apps built with Slack APIs, whether those apps are "unlisted" (published outside of the Marketplace) or templatized one-off "custom" apps.
Data Usage Restrictions: We're reinforcing safeguards around how data accessed via Slack APIs can be stored, used, and shared.
API-Specific Terms: We're providing clearer guidance on how to use certain APIs, such as the Discovery API and the Data Access API, responsibly.
The majority of developers will not see any changes to Slack APIs. We're making targeted rate limit changes to two specific Web API methods: the conversations.history and conversations.replies methods, only for apps outside of the Slack App Marketplace. These methods are designed to facilitate an app reading a comment or a thread, but in the hands of unvetted applications have the potential to exfiltrate large amounts of sensitive conversational data. To help keep workspace data secure and prevent bulk data exfiltration by unvetted applications, these methods will have a new rate limit of 15 messages per request at one request per minute. Marketplace apps will not see a rate limit change.
We're also announcing new, off-platform capabilities for our Real-time Search API, currently available only to select partners.
As AI systems become more powerful, so do the risks associated with how customer data is accessed and used. Slack is strengthening and clarifying our policies so we can better safeguard customers and support innovation while preventing unsanctioned data scraping and abuse.
As noted in the Slack Developer Policy, the Slack Marketplace has always been the intended home for secure, high-quality apps. Slack does not charge for Marketplace inclusion, so it is open to developers who meet Marketplace guidelines and submit for review. While Slack does not certify or endorse apps, before an app can be published on the Marketplace, we perform a security review and analyze the scopes that an application requests in light of its functionality. This process bolsters customer confidence in their tools and helps ensure the security of the Slack ecosystem. Unlisted apps, by contrast, are for development and testing—not large-scale or commercial distribution. With these updates to the API Terms of Service, we're now making that distinction even clearer.
Along with these policy changes, we are implementing targeted rate limits to two conversations methods to focus on the applications that may be putting customer data most at risk—unvetted applications potentially pulling large amounts of customer data.
Finally, we recognize that customers and developers are eager to safely capitalize on the valuable business knowledge stored in Slack conversations. We're announcing new, off-platform capabilities in our Real-time Search API that will unlock possibilities for Marketplace applications to facilitate exciting new AI use cases.
These terms updates apply to all development with Slack APIs, but Marketplace apps that abide by the Slack Marketplace guidelines should not see any changes.
While these terms changes apply to all development using Slack APIs, the majority of developers will not notice any changes for the time being.
If you don't call the conversations.history or conversations.replies Web API methods, you will likely not see any rate limit changes or enforcement for the time being. But the Marketplace is ultimately the right destination for all commercially distributed apps, so if you commercially distribute your application, you should explore the listing process and review the Slack Marketplace guidelines to understand how to make your app suitable for the Marketplace.
Developers who are affected by rate limit changes or enforcement will receive notice with more detailed information about how their app is affected and what to do next. Most notably, starting today, new installs of non-Marketplace apps will see lower rate limits for the conversations.history and the conversations.replies Web API methods. To help keep workspace data secure and prevent bulk data exfiltration by unvetted applications, these methods will have a new rate limit of 15 messages per request at one request per minute.
While we understand customers and developers want to enhance their applications with data from Slack, bulk downloads of customers' conversational data for indexing and querying pose risks of exposing sensitive information and undermining Slack access controls, such as private channel membership.
Our Real-time Search API helps meet this need, giving you a better, safer way to access Slack channel data after these changes. It allows for real-time querying of Slack data without storing it, allowing customers and developers to take advantage of the wealth of knowledge in Slack with a more targeted approach that doesn't necessitate storing sensitive conversational data. It's currently in a limited beta with select partners. Stay tuned for announcements on the general availability of this API.
Please review the Marketplace guidelines for a detailed look at the types of applications suitable for the Marketplace and guidance on how best to use methods and scopes for your use cases.
Note the Real-time Search API, which facilitates real-time search and data access, may unlock use cases that previously would not have been approved for the Marketplace.
If you see an increase in rate limit errors, please refer to our guide on how to respond to rate limit conditions. Most apps do not need the ability to read the full content of a channel, so if you're running into rate limit errors, consider the other ways the platform may provide to get the kind of focused, contextual information an app typically requires, such as the Events API or the forthcoming Real-time Search API.
Most apps are unaffected by these changes. Apps already using the conversations.history and conversations.replies Web API methods will continue to function, but new installations may encounter additional rate limit errors unless they approved for the Slack Marketplace. On September 2, 2025, these rate limits will impact existing installations of these apps. Any new publicly distributed apps you create may encounter additional rate limit errors unless they are submitted to the Slack Marketplace.